[tor-bugs] #9002 [Tor]: Clients should discard v2 HS descriptors with more than 10 intro points

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#9002: Clients should discard v2 HS descriptors with more than 10 intro points
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 Reporter:  rransom              |          Owner:  mikeperry         
     Type:  defect               |         Status:  needs_review      
 Priority:  critical             |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                  |        Version:                    
 Keywords:  023-backport tor-hs  |         Parent:  #9001             
   Points:                       |   Actualpoints:                    
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Comment(by rransom):

 Replying to [comment:7 andrea]:
 > This patch looks reasonable to me; only thing to really question is the
 choice of MAX_INTRO_POINTS.  Do we know how hidden service reliability
 varies as a function of the number of intro points to justify the choice
 and the phrasing "(misguided) attempt to improve reliability" in the
 warning?

 Publishing more intro points in a descriptor should spread the circuit-
 extension load of client intro circuits over more relays so that clients
 are less likely to overload the intro-point relays.  See #3825 for what
 happens if clients do overload a relay; in short, if they fail to extend
 their circuit to the intro point, they used to repeatedly try again, thus
 keeping the relay overloaded.  (I fixed that; now they only pound each
 intro point a few times before giving up on it.)

 The maximum number of intro points which will improve a hidden service's
 reliability is 6, because each HS publishes its descriptor to at most 6
 HSDir relays.  I picked 10 as the maximum in #3825 because I wanted to
 never have to worry about that bottleneck again.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9002#comment:9>
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